Infrared transmission polyolefin film, and preparation method therefor and use thereof

Abstract

Provided in the present application are an infrared transmission polyolefin film, and a preparation method therefor and the use thereof. The infrared transmission polyolefin film comprises a composite layer, a core layer and a heat seal layer, which are sequentially stacked, wherein the composite layer comprises the following components: a polyolefin resin, an infrared transmission masterbatch and a processing aid; the core layer comprises the following components: a polyolefin resin, an infrared transmission masterbatch, a light stabilizer and a processing aid; the heat seal layer comprises the following components: a polyolefin resin and a processing aid; and the infrared transmission masterbatch comprises the following components in parts by weight: 45-59 parts of a polyolefin resin, 40-50 parts of an infrared transmission pigment, 0.5-3 parts of an antioxidant and 0.5-2 parts of a processing aid. A backsheet made of the infrared transmission polyolefin film reduces the temperature of an assembly, improves the power generation efficiency of cells, and also has good ultraviolet resistance and good moisture resistance.

Description

Infrared-transmitting polyolefin film, preparation method thereof, and application thereof Technical Field

[0001] The present application relates to the technical field of plastic films, for example, an infrared-transmitting polyolefin film and a preparation method and application thereof. Background Art

[0002] The spectrum of sunlight received by Earth can be divided into three main wavelengths, each contributing a different proportion of the total energy. The ultraviolet (UV) region, 280nm-380nm, accounts for 5% of the total solar energy received by Earth; the visible (VIS) region, 380nm-780nm, accounts for approximately 45% of the total solar energy received by Earth; and the infrared (IR) region, 780nm-2500nm, accounts for 50% of the total solar energy received by Earth. Most of this energy is concentrated in the short-wave near-infrared region, 780nm-1100nm. Solar cells generate electricity by absorbing sunlight in the 400-1100nm wavelength range. With increasing demands for energy conservation and environmental protection, the photovoltaic industry is constantly researching ways to more efficiently utilize sunlight. Currently, white, black, and transparent backsheets are available on the market. White backsheets contain titanium dioxide, which reflects 90% of visible and infrared light, effectively utilizing sunlight and reducing component temperatures. However, the color is often too monotonous. The application of transparent backsheets is currently limited, so black backsheets are increasingly popular in the market. However, the pigment used in existing black backsheets is almost entirely carbon black, which absorbs almost all visible and infrared light, causing module temperatures to rise and reducing power generation efficiency. To improve the reflectivity of black backsheets, it is necessary to avoid increasing the reflectivity of visible light, otherwise the color of the backsheet will be changed. Therefore, it is particularly important to design a backsheet that can reflect in the infrared region, especially the near-infrared region.

[0003] CN115926545A provides a weather-resistant black coating, its preparation method, and application. The weather-resistant black coating comprises a specific number of parts of a weather-resistant resin, a pigment composition, and a curing agent. The pigment composition comprises a combination of pigment yellow, pigment blue, and pigment red. By using the above three colors of pigments to form a black pigment composition, the resulting weather-resistant black coating not only has high infrared transmittance but also excellent weather resistance. Therefore, when the weather-resistant black coating is used in conjunction with a substrate having an infrared reflective function and applied to a photovoltaic solar backsheet, the resulting photovoltaic solar backsheet has a high reflectivity in the 750-1200nm band, thereby effectively increasing the utilization rate of light and improving the power generation efficiency of the solar photovoltaic module. However, the water vapor transmission rate of the backsheet using the functional coating needs to be further reduced.

[0004] CN111421935A provides an infrared-reflective polyolefin film, its preparation method, and application. The infrared-reflective polyolefin film comprises a composite layer, a core layer, and a heat-seal layer stacked in sequence. The composite layer is made from polyolefin resin and a processing aid. The core layer is made from polyolefin resin, an infrared-reflective pigment, a UV stabilizer, and an antioxidant. The heat-seal layer is made from polyolefin resin and a processing aid. The infrared-reflective polyolefin film has a high reflectivity in the infrared region. Backsheets made from the film can achieve a reflectivity of 40-60% in the 780-1100nm band and exhibit excellent UV resistance and water-blocking properties. However, infrared-reflective backsheets made from films made with reflective pigments still require improvement in terms of reflectivity and water-blocking properties.

[0005] Therefore, developing a black solar cell backplane that has high reflectivity, low water permeability, and excellent UV resistance in the near-infrared region is an urgent problem to be solved in this field.

[0006] Summary of the Invention

[0007] The following is a summary of the subject matter described in detail herein. This summary is not intended to limit the scope of the claims.

[0008] The present application provides an infrared-transmitting polyolefin film, a preparation method, and an application thereof. The infrared-transmitting polyolefin film is prepared into a polyvinyl fluoride (PVF) / polyethylene terephthalate (PET) / polyethylene (PE) backboard. Infrared light in the 780-1100nm band can effectively penetrate the PE layer and reach the PET layer, and the infrared light is reflected back by utilizing the reflectivity of the PET sheet.

[0009] In a first aspect, the present application provides an infrared-transmitting polyolefin film, wherein the infrared-transmitting polyolefin film comprises a composite layer, a core layer, and a heat-sealing layer stacked in sequence.

[0010] The components of the composite layer include: polyolefin resin, infrared transmission masterbatch and processing aid;

[0011] The components of the core layer include: polyolefin resin, infrared transmission masterbatch, light stabilizer and processing aid;

[0012] The components of the heat sealing layer include polyolefin resin and processing aid.

[0013] In one embodiment, the components of the infrared transmitting masterbatch include, by weight, 45-59 parts of polyolefin resin, 40-50 parts of infrared transmitting pigment, 0.5-3 parts of antioxidant and 0.5-2 parts of processing aid.

[0014] The weight proportion of the polyolefin resin in the components of the infrared transmitting masterbatch is 45-59 parts, for example, it can be 45 parts, 46 parts, 48 ​​parts, 50 parts, 52 parts, 54 parts, 55 parts, 59 parts, and specific point values ​​between the above points. Due to space limitations and for the sake of simplicity, this application no longer exhaustively lists the specific point values ​​included in the range.

[0015] The weight proportion of the infrared transmitting pigment in the components of the infrared transmitting masterbatch is 40-50 parts, for example, it can be 41 parts, 42 parts, 45 parts, 46 parts, 48 ​​parts, 50 parts, and specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, this application no longer exhaustively lists the specific point values ​​included in the range.

[0016] The weight proportion of the antioxidant in the components of the infrared transmitting masterbatch is 0.5-3 parts, for example, it can be 0.5 parts, 1 parts, 1.5 parts, 2 parts, 2.5 parts, 3 parts, and specific point values ​​between the above points. Due to space limitations and for the sake of simplicity, this application no longer exhaustively lists the specific point values ​​included in the range.

[0017] The weight portion of the processing aid in the components of the infrared transmitting masterbatch is 0.5-2 parts, for example, it can be 0.5 parts, 1 part, 1.5 parts, 2 parts, and specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, this application no longer exhaustively lists the specific point values ​​included in the range.

[0018] In one embodiment, the polyolefin resin in the components of the infrared transmitting masterbatch includes a combination of low density polyethylene and linear low density polyethylene.

[0019] In one embodiment, the mass ratio of the low-density polyethylene and the linear low-density polyethylene is (1-3):1, for example, it can be 1:1, 2:1, 3:1, and specific point values ​​between the above point values. Due to limited space and for the sake of simplicity, this application no longer exhaustively lists the specific point values ​​included in the range.

[0020] In one embodiment, the melt index of the polyolefin resin in the infrared-transmitting masterbatch at 190° C. and 2.16 kg is 5-20 g / 10 min, for example, 5 g / 10 min, 10 g / 10 min, 15 g / 10 min, 20 g / 10 min, and specific values ​​between the above values. Due to space limitations and for the sake of brevity, this application does not exhaustively list the specific values ​​included in the above range. The antioxidant includes antioxidant 1076 and / or antioxidant 168.

[0021] In one embodiment, the processing aid in the components of the infrared transmitting masterbatch includes a fluoropolymer processing aid (PPA) and / or an anti-blocking agent.

[0022] In one embodiment, the infrared transmitting pigment comprises a combination of pigment violet and pigment green.

[0023] In one embodiment, the molecular formula of Pigment Violet is C 24 H 10 N2O4, molecular weight is 390.35.

[0024] In one embodiment, the molecular formula of pigment green is C 40 H 26 N2O6, molecular weight is 630.64.

[0025] In one embodiment, the mass ratio of the pigment violet to the pigment green is 1:(1.5-2.5), for example, it can be 1:1.5, 1:1.8, 1:2, 1:2.2, 1:2.5, and specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, this application no longer exhaustively lists the specific point values ​​included in the range.

[0026] In one embodiment, the preparation method of the infrared transmission masterbatch comprises:

[0027] The polyolefin resin, infrared transmission pigment, antioxidant and processing aid are mixed, melt-extruded and granulated to obtain the infrared transmission masterbatch.

[0028] In one embodiment, the mixing is carried out under stirring conditions, and the stirring rate is 500-1000 rpm, for example, it can be 500 rpm, 600 rpm, 700 rpm, 800 rpm, 900 rpm, 1000 rpm, and specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, this application no longer exhaustively lists the specific point values ​​included in the range.

[0029] In one embodiment, the melt extrusion is performed in a twin-screw extruder.

[0030] In one embodiment, the melt extrusion temperature is 160-210°C, for example, it can be 160°C, 170°C, 80°C, 190°C, 200°C, 210°C, and specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, this application no longer exhaustively lists the specific point values ​​included in the range.

[0031] In one embodiment, the thickness of the infrared-transmitting polyolefin film is 150-200 μm, for example, it can be 150 μm, 160 μm, 180 μm, 190 μm, 200 μm, and specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, this application no longer exhaustively lists the specific point values ​​included in the range.

[0032] In one embodiment, the thickness ratio of the composite layer, the core layer and the heat-sealing layer is 1:(2-3):(1-2), for example, it can be 1:2:1, 1:2.2:1, 1:2.4:1, 1:2.6:1, 1:2.8:1, 1:3:1, 1:2:2, 1:2.2:2, 1:2.4:2, 1:2.6:2, 1:2.8:2, 1:3:2, and specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, this application no longer exhaustively lists the specific point values ​​included in the range, and 1:(2-3):1 can be selected.

[0033] In one embodiment, the components of the composite layer include, by weight, 85-99.8 parts of polyolefin resin, 0.1-10 parts of infrared transmission masterbatch, and 0.1-5 parts of processing aid.

[0034] The weight proportion of the polyolefin resin in the components of the composite layer is 85-99.8 parts, for example, it can be 85 parts, 86 parts, 88 parts, 90 parts, 95 parts, 99 parts, 99.8 parts, and specific point values ​​between the above points. Due to space limitations and for the sake of simplicity, this application no longer exhaustively lists the specific point values ​​included in the range.

[0035] The weight proportion of the infrared transmitting masterbatch in the components of the composite layer is 0.1-10 parts, for example, it can be 0.1 parts, 0.5 parts, 1 parts, 2 parts, 3 parts, 5 parts, 6 parts, 8 parts, 10 parts, and specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, this application no longer exhaustively lists the specific point values ​​included in the range.

[0036] The weight proportion of the processing aid in the components of the composite layer is 0.1-5 parts, for example, it can be 0.1 parts, 1 parts, 2 parts, 3 parts, 4 parts, 5 parts, and specific values ​​between the above points. Due to space limitations and for the sake of simplicity, this application no longer exhaustively lists the specific points included in the range.

[0037] In one embodiment, the core layer comprises, by weight, 80-94.4 parts of polyolefin resin, 5-10 parts of infrared transmission masterbatch, 0.5-5 parts of light stabilizer, and 0.1-5 parts of processing aid.

[0038] The weight proportion of the polyolefin resin in the components of the core layer is 80-94.4 parts, for example, it can be 80 parts, 85 parts, 90 parts, 94 parts, 94.4 parts, and specific point values ​​between the above point values. Due to limited space and for the sake of simplicity, this application no longer exhaustively lists the specific point values ​​included in the range.

[0039] The weight proportion of the infrared transmitting masterbatch in the components of the core layer is 5-10 parts, for example, it can be 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, and specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, this application no longer exhaustively lists the specific point values ​​included in the range.

[0040] The weight proportion of the light stabilizer in the components of the core layer is 0.5-5 parts, for example, it can be 0.5 parts, 1 parts, 2 parts, 3 parts, 4 parts, 5 parts, and specific values ​​between the above points. Due to space limitations and for the sake of simplicity, this application no longer exhaustively lists the specific points included in the range.

[0041] The weight proportion of the processing aid in the components of the core layer is 0.1-5 parts, for example, it can be 0.1 parts, 0.5 parts, 1 parts, 2 parts, 3 parts, 4 parts, 5 parts, and specific point values ​​between the above points. Due to space limitations and for the sake of simplicity, this application no longer exhaustively lists the specific point values ​​included in the range.

[0042] In one embodiment, the heat seal layer comprises, by weight, 95-99.9 parts of polyolefin resin and 0.1-5 parts of processing aid.

[0043] The weight proportion of the polyolefin resin in the components of the heat seal layer is 95-99.9 parts, for example, it can be 95 parts, 96 parts, 97 parts, 98 parts, 99 parts, 99.9 parts, and specific values ​​between the above points. Due to space limitations and for the sake of brevity, this application no longer exhaustively lists the specific points included in the range.

[0044] The weight portion of the processing aid in the components of the heat seal layer is 0.1-5 parts, for example, it can be 0.1 parts, 0.5 parts, 1 parts, 2 parts, 3 parts, 4 parts, 5 parts, and specific values ​​between the above points. Due to space limitations and for the sake of brevity, this application no longer exhaustively lists the specific points included in the range.

[0045] In one embodiment, the polyolefin resins in the components of the composite layer, the core layer, and the heat-seal layer each independently comprise medium-density polyethylene and / or high-density polyethylene.

[0046] In one embodiment, the melt index of the polyolefin resin in the components of the composite layer, core layer and heat seal layer at 190°C and 2.16 kg is 1-5 g / 10 min, for example, it can be 1 g / 10 min, 2 g / 10 min, 3 g / 10 min, 4 g / 10 min, 5 g / 10 min, and specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, this application no longer exhaustively lists the specific point values ​​included in the range.

[0047] In one embodiment, the density of the polyolefin resin in the components of the composite layer, core layer and heat seal layer is 0.94-0.97 g / cm 3 , for example, it can be 0.94 g / cm 3 , 0.95g / cm 3 , 0.96g / cm 3 , 0.97g / cm 3 , as well as specific point values ​​between the above point values, due to space limitations and for the sake of brevity, this application no longer exhaustively lists the specific point values ​​included in the range.

[0048] In one embodiment, the antioxidant in the components of the composite layer, the core layer, and the heat seal layer includes antioxidant 1076 and / or antioxidant 168.

[0049] In one embodiment, the processing aids in the components of the composite layer, the core layer and the heat-seal layer include PPA and / or an anti-blocking agent.

[0050] In one embodiment, the light stabilizer includes light stabilizer UV3529 and / or light stabilizer 622.

[0051] In a second aspect, the present application provides a method for preparing the infrared-transmitting polyolefin film according to the first aspect, the preparation method comprising:

[0052] (1) blending the components of the composite layer, the core layer, and the heat-sealing layer to obtain composite layer composite particles, core layer composite particles, and heat-sealing layer composite particles, respectively;

[0053] (2) Melting and plasticizing the composite layer compound particles, the core layer compound particles and the heat-sealing layer compound particles obtained in step (1), extruding and shaping them to obtain the infrared-transmitting polyolefin film.

[0054] In one embodiment, the melt plasticization in step (2) is performed using a multi-layer co-extrusion casting device and / or a film blowing device.

[0055] In one embodiment, the temperature of the melt plasticization in step (2) is 170-250°C, for example, it can be 170°C, 180°C, 200°C, 220°C, 250°C, and specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, this application no longer exhaustively lists the specific point values ​​included in the range.

[0056] In one embodiment, the shaping in step (2) is cooling shaping.

[0057] In one embodiment, after step (2), the method further includes: subjecting the infrared reflective polyolefin film to corona treatment, and winding the film to obtain the infrared transmissive polyolefin film.

[0058] In the third part, the present application provides an application of the infrared-transmitting polyolefin film as described in the first aspect in the preparation of a black backplane for solar cells.

[0059] Compared with the related art, this application has the following beneficial effects:

[0060] The present application provides an infrared-transmitting polyolefin film, a preparation method, and an application thereof. The PVF / PET / PE backsheet prepared from the film can effectively penetrate the PE layer and reach the PET layer with infrared light in the 780-1100nm band. The infrared light is reflected back by utilizing the reflectivity of the PET sheet. The infrared light reflectivity of the prepared backsheet in the 780-1100nm band reaches 60.2-75%, thereby reducing the component temperature and improving the power generation efficiency of the battery cell. The infrared-transmitting polyolefin film uses a light stabilizer and a medium-high-density polyolefin resin, so that the backsheet has both excellent UV resistance and good moisture resistance, wherein the water vapor transmission rate is 0.43-2.5g / (m 2 24h), UV resistance is 200-350KWh / m 2 .

[0061] Still other aspects will become apparent upon reading and understanding the detailed description. DETAILED DESCRIPTION

[0062] The technical solution of the present application is further described below through specific implementation methods. Those skilled in the art should understand that the embodiments are only used to help understand the present application and should not be regarded as specific limitations of the present application.

[0063] The experimental materials used in the examples and comparative examples of this application are as follows:

[0064] (1) Pigment Violet, manufacturer BASF, brand name Pigment Violet 29;

[0065] (2) Pigment Green, manufacturer BASF, brand Pigment Green 32;

[0066] (3) Low-density polyethylene, manufactured by Hanwha, brand LD955;

[0067] (4) Linear low-density polyethylene, manufactured by Maoming Petrochemical, brand 7144;

[0068] (5) Medium density polyethylene, manufacturer ExxonMobil, brand 4009;

[0069] (6) High-density polyethylene, manufacturer Total, brand M6040;

[0070] (7) Light stabilizers, UV3529, 622;

[0071] (8) Antiblocking agent, manufacturer: Mitsui Chemicals, brand: EAZ-10;

[0072] (9)PPA, manufacturer: Shulman, brand: AMF705HF.

[0073] Preparation Example 1

[0074] This preparation example provides an infrared transmission masterbatch, wherein the components of the infrared transmission masterbatch include, by weight: 55 parts of polyolefin resin, 40 parts of infrared transmission pigment, 3 parts of antioxidant and 2 parts of processing aid;

[0075] The polyolefin resin is a combination of low-pressure polyethylene (LD955) and linear low-density polyethylene (7144), with a mass ratio of 1:1;

[0076] The infrared transmitting pigment is a combination of pigment violet 29 and pigment green 32, with a mass ratio of 1:2;

[0077] The antioxidant is 1076;

[0078] The processing aid is PPA;

[0079] The preparation method of the infrared transmission masterbatch comprises:

[0080] The polyolefin resin, infrared transmission pigment, antioxidant and processing aid are mixed at 500 rpm, melt-extruded at 180° C. through a twin-screw extruder, and granulated to obtain the infrared transmission masterbatch.

[0081] Preparation Example 2

[0082] This preparation example provides an infrared transmission masterbatch, wherein the components of the infrared transmission masterbatch include, by weight: 48 parts of polyolefin resin, 50 parts of infrared transmission pigment, 1 part of antioxidant and 1 part of processing aid;

[0083] The polyolefin resin is a combination of low-pressure polyethylene (LD955) and linear low-density polyethylene (7144), with a mass ratio of 2:1;

[0084] The infrared transmitting pigment is a combination of pigment violet 29 and pigment green 32, with a mass ratio of 1:3;

[0085] The antioxidant is 168;

[0086] The processing aid is PPA;

[0087] The preparation method of the infrared transmission masterbatch comprises:

[0088] The polyolefin resin, infrared transmission pigment, antioxidant and processing aid are mixed at 800 rpm, melt-extruded at 190° C. through a twin-screw extruder, and granulated to obtain the infrared transmission masterbatch.

[0089] Example 1

[0090] This embodiment provides an infrared-transmitting polyolefin film. The infrared-transmitting polyolefin film (150 μm thick) includes a composite layer (30 μm thick), a core layer (90 μm thick), and a heat-sealing layer (30 μm thick) stacked in sequence. The specific composition of each layer is shown in Table 1:

[0091] Table 1

[0092] The preparation method of the infrared-transmitting polyolefin film comprises:

[0093] 1. Blending the components of the composite layer, core layer and heat seal layer respectively to obtain composite layer composite particles, core layer composite particles and heat seal layer composite particles;

[0094] 2. The composite layer particles, core layer particles, and heat seal layer particles obtained in step 1 are melted and plasticized at 230° C. in a multi-layer co-extrusion casting device, extruded through a die, and cooled and shaped to obtain the infrared reflective polyolefin film;

[0095] 3. The infrared reflective polyolefin film obtained in step 2 is subjected to corona treatment and wound up to obtain a finished product.

[0096] Example 2

[0097] This embodiment provides an infrared-transmitting polyolefin film. The infrared-transmitting polyolefin film (180 μm thick) includes a composite layer (40 μm thick), a core layer (100 μm thick), and a heat-sealing layer (40 μm thick) stacked in sequence. The specific composition of each layer is shown in Table 2:

[0098] Table 2

[0099] The preparation method of the infrared-transmitting polyolefin film comprises:

[0100] 1. Blending the components of the composite layer, core layer and heat seal layer respectively to obtain composite layer composite particles, core layer composite particles and heat seal layer composite particles;

[0101] 2. The composite layer particles, core layer particles, and heat seal layer particles obtained in step 1 are melted and plasticized at 200° C. in a multi-layer co-extrusion film blowing device, extruded through a die, and cooled and shaped to obtain the infrared reflective polyolefin film;

[0102] 3. The infrared reflective polyolefin film obtained in step 2 is subjected to corona treatment and wound up to obtain a finished product.

[0103] Example 3

[0104] This embodiment provides an infrared-transmitting polyolefin film. The infrared-transmitting polyolefin film (thickness 200 μm) includes a composite layer (thickness 50 μm), a core layer (thickness 100 μm), and a heat-sealing layer (thickness 50 μm) stacked in sequence. The specific composition of each layer is shown in Table 3:

[0105] Table 3

[0106] The preparation method of the infrared-transmitting polyolefin film comprises:

[0107] 1. Blending the components of the composite layer, core layer and heat seal layer respectively to obtain composite layer composite particles, core layer composite particles and heat seal layer composite particles;

[0108] 2. The composite layer particles, core layer particles, and heat seal layer particles obtained in step 1 are melted and plasticized at 200° C. in a multi-layer co-extrusion film blowing device, extruded through a die, and cooled and shaped to obtain the infrared reflective polyolefin film;

[0109] 3. The infrared reflective polyolefin film obtained in step 2 is subjected to corona treatment and wound up to obtain a finished product.

[0110] Example 4

[0111] This embodiment provides an infrared-transmitting polyolefin film, which differs from Example 1 only in that the medium-density polyethylene in the raw materials for preparing the composite layer, core layer and heat-sealing layer is replaced by linear low-density polyethylene 7042, and the content of other raw materials and the preparation method of each layer are the same as those in Example 1.

[0112] Example 5

[0113] This embodiment provides an infrared-transmitting polyolefin film. The difference between the infrared-transmitting polyolefin film and Example 1 is that the thickness of the composite layer is 25 μm, the thickness of the core layer is 50 μm, and the thickness of the heat-sealing layer is 25 μm. The raw material content and preparation method of each layer are the same as those in Example 1.

[0114] Comparative Example 1

[0115] This comparative example provides a polyolefin film, which differs from Example 1 in that the infrared transmission masterbatch of the composite layer and the core layer is removed and replaced with a carbon black masterbatch of the same content, and the content of other raw materials and the preparation method of each layer are the same as those in Example 1.

[0116] Comparative Example 2

[0117] This comparative example provides an infrared-transmitting polyolefin film. The infrared-transmitting polyolefin film differs from Example 1 in that the light stabilizer in the core layer is removed, that is, the M6040 content in the core layer is 93%. The content of other raw materials and the preparation method of each layer are the same as those in Example 1.

[0118] Backplane performance test:

[0119] A 250 μm PET sheet with a reflectivity of 85% was coated with glue on one side and laminated with a 25 μm PVF film. The other side was also coated with glue and laminated with the polyolefin films provided in Examples 1-5 and Comparative Examples 1-2. After aging, a black solar cell backsheet was obtained and its performance was tested. The specific method is as follows. The specific test results of the backsheet performance are shown in Table 4.

[0120] (1) Reflectivity: Tested in accordance with IEC 62805-2;

[0121] (2) Water vapor transmission rate: tested in accordance with the provisions of GB / T 26253;

[0122] (3) UV resistance: Photovoltaic industry standard UV test chamber, UV spectrum distribution complies with the relevant provisions of IEC 61215, test temperature 65°C.

[0123] Table 4

[0124] From the data in Table 1, it can be seen that the black solar cell backsheet made of the infrared-transmitting polyolefin film described in this application has a reflectivity of 60.2-75% in the 780-1100nm band and has excellent UV resistance, with a maximum UV resistance of 350KWh / m 2 , and excellent water barrier properties, water vapor transmission rate can be lower than 0.5g / (m 2 ·24h).

[0125] From the comparison between Example 1 and Example 4, it can be seen that the infrared transmission polyolefin film prepared by using only linear low-density polyethylene has a water vapor permeability of 2.5 g / (m 2 ·24h), while the use of medium / high density polyethylene greatly improves its water barrier performance; from the comparison between Example 1 and Comparative Example 1, it can be seen that the reflectivity of the backsheet made by using carbon black masterbatch instead of infrared transmitting masterbatch in the 780-1100nm band is extremely low; from the comparison between Example 1 and Comparative Example 2, it can be seen that the UV resistance of the backsheet made without ultraviolet light stabilizer is significantly reduced; from the comparison between Example 1 and Example 5, it can be seen that if the overall thickness of the infrared transmitting polyolefin film is reduced, the infrared reflectivity, water barrier performance and UV resistance of the composite backsheet will all decrease to varying degrees.

[0126] The applicant declares that while the above-mentioned embodiments are used to illustrate the infrared-transmitting polyolefin film, its preparation method, and its application, this application is not limited to the above-mentioned embodiments, and does not necessarily rely on the above-mentioned embodiments for implementation. Persons skilled in the art should understand that any improvements to this application, equivalent replacements for raw materials in the product of this application, addition of auxiliary components, and selection of specific methods, etc., fall within the scope of protection and disclosure of this application.

Claims

1. An infrared-transmitting polyolefin film, wherein: The infrared transmission polyolefin film comprises a composite layer, a core layer and a heat sealing layer stacked in sequence; The components of the composite layer include: polyolefin resin, infrared transmission masterbatch and processing aid; The components of the core layer include: polyolefin resin, infrared transmission masterbatch, light stabilizer and processing aid; The components of the heat seal layer include: polyolefin resin and processing aid; The components of the infrared transmission masterbatch include, by weight, 45-59 parts of polyolefin resin, 40-50 parts of infrared transmission pigment, 0.5-3 parts of antioxidant and 0.5-2 parts of processing aid.

2. The infrared-transmitting polyolefin film according to claim 1, wherein The polyolefin resin in the components of the infrared transmission masterbatch includes a combination of low-density polyethylene and linear low-density polyethylene.

3. The infrared-transmitting polyolefin film according to claim 2, wherein: The mass ratio of the low-density polyethylene to the linear low-density polyethylene is (1-3):

1.

4. The infrared-transmitting polyolefin film according to any one of claims 1 to 3, wherein: The melt index of the polyolefin resin in the components of the infrared transmission masterbatch is 5-20 g / 10 min at 190° C. and 2.16 kg.

5. The infrared-transmitting polyolefin film according to any one of claims 1 to 4, wherein: The antioxidant includes antioxidant 1076 and / or antioxidant 168; Optionally, the infrared transmission pigment comprises a combination of pigment violet and pigment green; Optionally, the mass ratio of the pigment violet to the pigment green is 1:(1.5-2.5); Optionally, the processing aid in the components of the infrared transmission masterbatch includes a fluorine-containing polymer processing aid and / or an opening agent.

6. The infrared-transmitting polyolefin film according to any one of claims 1 to 5, wherein: The preparation method of the infrared transmission masterbatch comprises: The polyolefin resin, the infrared transmission pigment, the antioxidant and the processing aid are mixed, melt-extruded and granulated to obtain the infrared transmission masterbatch; Optionally, the mixing is performed under stirring conditions, and the stirring rate is 500-1000 rpm; Optionally, the melt extrusion is carried out in a twin-screw; Optionally, the temperature of the melt extrusion is 160-210°C.

7. The infrared-transmitting polyolefin film according to any one of claims 1 to 6, wherein: The infrared-transmitting polyolefin film has a thickness of 150-200 μm; Optionally, the thickness ratio of the composite layer, the core layer and the heat-sealing layer is 1:(2-3):(1-2), and optionally 1:(2-3):

1.

8. The infrared-transmitting polyolefin film according to any one of claims 1 to 7, wherein: The components of the composite layer include, by weight: 85-99.8 parts of polyolefin resin, 0.1-10 parts of infrared transmission masterbatch and 0.1-5 parts of processing aid; Optionally, the components of the core layer include, by weight: 80-94.4 parts of polyolefin resin, 5-10 parts of infrared transmission masterbatch, 0.5-5 parts of light stabilizer and 0.1-5 parts of processing aid; Optionally, the components of the heat-sealing layer include, by weight: 95-99.9 parts of polyolefin resin and 0.1-5 parts of processing aid.

9. The infrared-transmitting polyolefin film according to claim 8, wherein: The polyolefin resins in the components of the composite layer, the core layer and the heat-sealing layer each independently include medium-density polyethylene and / or high-density polyethylene; Optionally, the melt index of the polyolefin resin in the components of the composite layer, the core layer and the heat-sealing layer is 1-5 g / 10 min at 190° C. and 2.16 kg; Optionally, the density of the polyolefin resin in the components of the composite layer, the core layer and the heat-sealing layer is 0.94-0.97 g / cm 3 ; Optionally, the antioxidant in the components of the composite layer, the core layer and the heat seal layer includes antioxidant 1076 and / or antioxidant 168; Optionally, the processing aid in the components of the composite layer, the core layer and the heat seal layer includes a fluorinated polymer Processing aids and / or antiblocking agents; Optionally, the light stabilizer includes light stabilizer UV3529 and / or light stabilizer 622.

10. A method for preparing the infrared-transmitting polyolefin film according to any one of claims 1 to 9, comprising: (1) blending the components of the composite layer, the core layer and the heat-sealing layer to obtain composite layer composite particles, core layer composite particles and heat-sealing layer composite particles, respectively; (2) Melting and plasticizing the composite layer particles, the core layer particles and the heat-sealing layer particles obtained in step (1), extruding and shaping, to obtain the infrared-transmitting polyolefin film.

11. The preparation method according to claim 10, wherein: The melt plasticization in step (2) is carried out using a multi-layer co-extrusion casting device and / or a film blowing device.

12. The preparation method according to claim 10 or 11, wherein: The temperature of the melt plasticization in step (2) is 170-250°C.

13. The preparation method according to claim 10, wherein: The shaping in step (2) is cooling shaping.

14. The preparation method according to any one of claims 10 to 13, wherein: After step (2), the method further includes: subjecting the infrared reflective polyolefin film to corona treatment, and winding and wrapping the film to obtain the infrared transmissive polyolefin film.

15. Use of the infrared-transmitting polyolefin film according to any one of claims 1 to 9 in preparing a black backplane film for solar cells.

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